• Korean Journal of Materials Research
• /
• v.32 no.3
• /
• pp.146-152
• /
• 2022

One disadvantage of deep cycle flooded lead-acid batteries is increasing water loss caused by use of (+) Pb-Sb / (-) Pb-Sb alloy grid. Water loss is generated by the emission of hydrogen gas from the (-) electrode during battery charging. In this paper, we maintain cycle life aspect through the development of hybrid flooded lead-acid batteries to which a (+) Pb-Sb / (-) Pb-Ca grid is applied and deal with the improvement of water loss. The amount of water loss compared to that of the (-) Pb-Sb grid decreased when Ca was added to the (-) Pb grid. For the (-) Pb-Ca grid, it was confirmed that the time to reach 0.0 V, at which water decomposition occurs, was increased compared to that of the (-) Pb-Sb grid at the NPV (Negative Potential Voltage). In the cycle life test conducted with the BCI (Battery Council International) standard, compared to the (+) Pb-Ca grid, the (+) Pb-Sb grid increased the life cycle of the batteries and the (+) Pb-Ca grid showed an early end of life due to PbO corrosion layer generation, as determined through SEM / EDS and Tear Down analysis. In conclusion, by addition of Sb to (+) Pb grid and Ca to (-) Pb grid, we developed a hybrid flooded lead-acid battery that meets user requirements to improve water loss characteristics and preserve cycle life characteristics.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.1
• /
• pp.53-57
• /
• 2010

The influence of CaO addition on the crystallization temperature, crystal types, and microstructure of L-A-S ($Li_2O-Al_2O_3-SiO_2$) glass-ceramics system fabricated from a coal bottom ash, produced at thermal power plant, was studied. The glass transition and crystallization temperatures were shifted to the higher temperature position with increasing CaO content in a non-isothermal analysis using a DTA. The major crystalline phases of L-A-S glass-ceramics system produced were identified as ${\beta}$-spodumene ($LiAlSi_2O_6$) and eucryptite ($LiAlSiO_4$). The glass-ceramics showed a bulk and surface crystallization behavior at a time. With increasing CaO content, the ${\beta}$-spodumene peak in XRD increased and some CaO-related phases were formed. The surface crystal grown from the exterior to the center in glass-ceramics showed various shapes by amount of CaO added. Some cracks were generated at the glass-ceramics containing CaO above 9 wt% due to the mismatch of thermal expansion coefficients between a ${\beta}$-spodumene and CaO-related crystal phases.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.823-828
• /
• 1999

Blast furnace slag cement(BSC) has many merits in relation to its prodution cost or environmental problem of these days, but it has still some limitation in broad use mainly because it has the lower early hydration strength than the normal portland cement(PC) has. In the present study, several different experimental concepts to improve its low strength in the early hydration stage were tried out which addition of the effective alkali activators such as Ca(OH)2 and limestone powder, fly ash in existing BSC. It was found that the addition of suitable quantity the effective alkali activators such as Ca(OH)2 and limestone powder, fly ash in BSC can be a possible way to get enough early strength compared with the PC and existing BSC.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.1
• /
• pp.113-118
• /
• 2006

In this work, we observed the changes in mass difference according to Al-foam's amount of Ca contents which depends on the viscosity control of fusion, quality of foamed addition, mixing, temperature tests. These are crucial influencing factors in determining foam-metal's size in the manufacturing process. In order to obtain the specimen, we changed the specific gravity from 0.2 to 0.3 for the study of the light weight, and obtained the optimal values of specific gravity, and then showed the mechanical characteristics of ultra-lightweight metal according to the changing mass. The optimal conditions for aluminum foam is when the addition of Ca content in $1.5wt\%~2.0wt\%$

• Journal of Korea Foundry Society
• /
• v.31 no.2
• /
• pp.79-82
• /
• 2011

Various grain refining alloying elements such as Sr, TiB, and Ca were added to AZ91D and their effects on the mechanical properties and mold filling ability were investigated. The average grain sizes of those alloys were significantly reduced by the small amounts of the alloying elements. Ca addition was the most remarkably effective in reducing the grain size, however it was found to deteriorate the mold filling ability and tensile properties. TiB addition was observed to be the most efficient for both grain refinement and mold filling.

• Journal of the Korean Ceramic Society
• /
• v.18 no.3
• /
• pp.147-151
• /
• 1981

On the calcium silicate hydrothermal reaction, the effect of NaOH and KOH Studied. Forincreasing the yield of fibers and to promote crystal growth, Rotary autoclae has been used. By addition NaOH solution, approximately 150${\mu}{\textrm}{m}$ of pectolite was grown. By addition KOH solution, approximately 30${\mu}{\textrm}{m}$ of 11$\AA$-Tobermorite was grown under the conditon of 21$0^{\circ}C$ 10 days reaction. These results indicate that 11$\AA$-Tobermorite was stabilized by KOH over a wide Temperature and composition range.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.6
• /
• pp.3937-3940
• /
• 2013

Objective: To explore the expression and significance of estrogen receptor (ER), progestrone receptor (PR), vascular endothelial growth factor (VEGF), CA15-3, CA125 and carcinoma embryonic antigen (CEA) expression in judging the prognosis of breast cancer. Materials and Methods: Sixty-five patients with breast cancer undergoing operations in the general surgery department were considered as the observation group, and 50 healthy outpatients of our hospital as the control group. Cubital venous blood was drawn in the morning from fasting patients in the two groups and chemiluminescence immunoassays were used to detect the levels of CA15-3, CA125 and CEA in serum. The follow-up duration was from 4 months to 2 years, and change in levels of the indicators was detected by dynamically drawing blood. After surgery, cancer tissue samples of patients in observation group remained on file (the non-recurrent patients were biopsied). Immunohistochemistry was applied to determine the expression of ER, PR and VEGF in tissue. Results: The effective rate of 12 patients with negative ER and PR expression was 33.3% in the observation group, being associated with prognosis to varying extents. Serum CA15-3, CA125 and CEA in the observation group were all significantly higher than in control group (p<0.01). With increase in pathological staging, levels of serum CA15-3, CA125 and CEA gradually increased (p<0.01). Levels in patients with lymph node metastasis were markedly higher than in those without (p<0.01). In addition, values with distal lymph node metastasis were notably higher than with adjacent lymph node metastasis (p<0.01). The postoperative follow-up results revealed that positive VEGF and levels of serum VEGF, CA15-3, CA125 and CEA in recurrence group were obviously higher than in non-recurrence group (p<0.01). Conclusions: Joint detection of ER and PR expression as well as levels of serum VEGF, CA15-3, CA125 and CEA is meaningful and can guide the diagnosis and treatment for breast cancer.

• Journal of the Korea Concrete Institute
• /
• v.29 no.4
• /
• pp.399-406
• /
• 2017

CaO-based by-product, which consist of CaO, $SO_3$, $Al_2O_3$ and so on, has being used to raw materials of CaO compound. When It was applied to recycling water of remicon, concrete performance can be enhanced because hydration reaction of powder material is accelerated. In this study, activated-sludge, which was putted desulfurization gypsum of CaO-based in recycling water, was manufactured to verify effect of them, and then they was investigated by characteristics of cement matrix and mortar. As a results, they indicated reduction of setting time and high soundness in cement matrix, and acceleration of hydration reaction can be verified by XRD analysis. Also, it can be maintained good workability if water content by usage of desulfurization gypsum, which used for production of activated-sludge, was adjusted. In addition, it can be verified strength development by activated-sludge although cement content by usage of desulfurization gypsum was reduced.

• Korean Journal of Food Science and Technology
• /
• v.24 no.2
• /
• pp.154-159
• /
• 1992

An investigation was carried out to study the feasibility of tofu preparation with using isolated soyprotein(ISP) only. The ISP tofu was prepared by boiling the ISP suspension for 2 min before addition of coagulants. Effects of coagulants($CaSO_{4},\;CaCl_{2}\;MgCl_{2}\;GDL$) and coagulation temperature in the range of $2{\sim}95^{\circ}C$ were studied on the amounts of coagulants required, size and shape of coagulates, volume yield and textural properties of tofu. It was found that amounts of coagulants and tofu volume was significantly reduced and the larger and cloud-like shape was obtained as the coagulation temperature increased. A rather precipitation was occured under $40\;or\;50^{\circ}C$, which caused difficulty for tofu formation by pressing. GDL and $CaSO_{4}$ showed higher yields than those of $CaCl_{2}\;and\;MgCl_{2}$ at low temperature range and little difference at high temperature. In the textural properties of hardness, brittleness and gumminess of tofu were almost lineary and rapidly increased as the coagulation temperature increased where $CaCl_{2}\;and\;GDL$ produced highest and lowest of those values, respectively. The elasticity was reduced as the temperature increased for those made with $MaCl_{2},\;CaSO_{4}\;GDL\;and\;CaCl_{2}$, tofu showed little change.

• Korean Journal of Environmental Agriculture
• /
• v.25 no.3
• /
• pp.276-283
• /
• 2006

To evaluate the effectiveness of the foliar spray of calcium on "Baekdo" peach fruit, we carried out experiments in the orchards. The sprays were applied with $CaCl_2\;(Ca:\;400mg.kg^{-1})\;and\;CaCl_2$ with adjuvants (amino acid, $2g.kg^{-1}$; phytic acid, $2ml.kg^{-1}$ and wood vinegar, $2ml.kg^{-1}$) for four times from June 12 through July 4 at weekly intervals. The fruits and leaves were evaluated for Ca content, firmness and incidence of Brown rot caused by Monilinia fructicola at harvest To evaluate fruit quality included Ca content, firmness natural decay during the storage, the fruits were stored at room temperature for 14 days. The Ca content in leaf and fruit flesh at harvest was significantly increased (P=0.05) in $CaCl_2$ + amino acid treatment among $CaCl_2$ treatments. However, there was not significant Ca content in fruit peel. The firmness of flesh increased significantly (P=0.05) in $CaCl_2$ + amino acid treatment. The natural decay (Rhizopus stolonifers) during storage at the room temperature for 14 days, the fruit treated with $CaCl_2$ + wood vinegar exhibited lowest (P=0.05) incidence. Also, the firmness of the fruit during storage was firmer with treated $CaCl_2$ than untreated fruit. In the treatments of $CaCl_2$ + phytic acid and $CaCl_2$ + amino acid, it was possible to reduce incidence of Brown rot caused by M. fructicola most effectively in the field. In addition, inoculation with M. fructicola in fruits was also the most effective treatment for inhibiting disease development in vitro. These results suggested that the foliar spray of $CaCl_2$ with adjuvants increased the content of Ca and firmness of the fruits positively. It also inhibited the natural decay and the Brown rot effectively.